Split sheave continuously variable transmissions (CVTs) are used in a variety of recreational type off-road vehicles such as snowmobiles, all-terrain vehicles (ATVs), golf carts, and the like. CVTs, as their name implies, do not require shifting through a series of forward gears, but rather provide a continuously variable gear ratio that automatically adjusts as the vehicle speeds up or slows down, thus providing relatively easy operation for a rider. This automatic adjustment mechanism is advantageous to the rider because he need not be bothered by shifting gears for increasing or decreasing vehicle speed. However, this mechanism is also disadvantageous because, by its very function, the mechanism produces external stress to an endless belt that is utilized within the CVT. This external stress eventually causes the belt to break down, with the belt being torn apart or shredded.
Typically, CVTs are comprised of a drive clutch, a driven clutch, and the endless belt disposed about the clutches. The driven clutch includes a pair of opposed sheaves, which together define a generally V-shaped “pulley” within which the belt rides. The drive clutch is similarly configured with a pair of opposed sheaves.
As previously mentioned, while the operation of the CVT allows the rider to not be concerned with shifting gears, it also promotes external stress to the belt, eventually resulting in the belt breaking down and having to be replaced. While this is a well-known occurrence, it is also a general inconvenience for the rider, since he subsequently has to spend time and money buying and replacing the belt. If a CVT could be configured to somehow increase the operational lifetime of the belt running therein, it would be very beneficial to the rider and a valuable marketing tool for manufacturers of vehicles that utilize CVTs.